1. Think Aloud Protocol (TAP)
-A Reflection
By
Debaleena Chattopadhyay
Research Paper: Janni Nielsen, Torkil Clemmensen, and Carsten Yssing. 2002. Getting access to what goes
on in people's heads?: Reflections on the think-aloud technique. In Proceedings of the second Nordic
conference on Human-computer interaction (NordiCHI '02). ACM, New York, NY.

2. History
• What is TAP?
– TAP is a method to gather data in usability testing in product design and
development.*
– A usability testing protocol popularly used for its simplicity and effectiveness.
• Who introduced TAP in HCI?
– Clayton Lewis while at IBM in 1982. **
• What do TAPs involve?
– TAPs involve participants thinking aloud as they perform a set of specified
tasks. Users are asked to say whatever they are looking at, thinking, doing, and
feeling, as they go about their task.*
• What are the different types of TAPs?
– Concurrent TAP (collected during the task)*
– Retrospective Thinking (collected after the task)*
* From Wikipedia
** Presented in the technical report: Task-Centered User Interface Design: A Practical Introduction by C. Lewis and J. Rieman.
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3. Getting access to what goes on in
people’s heads?
• Thinking aloud technique dates back to the works of
experimental psychology and was first ever described by Karl
Duncker (1945) while he studied productive thinking.
• TAP is popularly used by usability researchers today. But what
do researchers think they get from TAP? Is it right to assume
that there is a one-to-one mapping between verbal protocols
and ‘pure data’?
• TAP adds cognitive load on users and can hinder primary tasks
(Preece, 1994). So how do the users experience it? What do
users think of it?
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4. Some applications of TAP
• Study search strategies and navigation behavior (Van
Waes, 1998)
• Understand mental processes in connection with
writing programs (Bringham, John & Lewis, 1991)
• Understand user’s reasoning while learning Smalltalk
(Koenemann-Belliveau et al. 1994)
• Study students’ writing and reading processes
• Investigate the cognitive processes involved in
problem solving.
Researchers argue that TAP allows them access to the
cognitive processes and mental behavior (Karsenty, 2001).
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5. What do we get access to when
asking users to think aloud?
• Does TAP really give us access to what goes on in
people’s heads?
Boren and Ramey(2000) has questioned the technique and its theoretical underpinnings. They
studied how practitioners actually carried out TAP sessions and discussed the practice in relation to
the classical work by Ericsson and Simon (1984) on vocalization and verbalization of thoughts. They
argue that it is necessary to have a firm theoretical grounding and a unified practice before the
technique can be called a method.
• The classical model of Ericsson and Simon (1984)on
verbal report as data*
This work wanted to reinstate verbal data as a valid resource for understanding human cognitive
processes to make it (a) possible to use verbal data to verify, not only discover, phenomena of
interest, provided (b) that verbal data was interpreted within a theoretical framework.
Such frameworks are necessary to investigate the construct validity, if there exists a one-to-one
mapping between useful information and introspective data.
* Protocol Analysis
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6. TAP in the light of Information
Processing Theory
• Everything we know has, at some point, gone
through our short-term memory (STM) and we
have been conscious of it.
• We can verbalize what we are perceiving while in
the process of perceiving, and we can verbalize
what we were conscious of if questioned shortly
after the process has taken place. This is because
it is still retained in our short-term memory.
• However, if there is a time span between
perceiving and the request to recall, we will
produce descriptions and explanations - not a
report of our immediate thoughts, because the
information from STM is lost.
• Using this assumption, we can distinguish
between (classical) introspection, retrospective
reports and communication to the experimenter
on the one hand, and on the other verbalization
of currently “heeded” thoughts (thoughts
reflecting current attention)
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7. Ericsson and Simon (1984) Model
• To study task directed cognitive processes – only
concurrent and certain kinds of retrospective
verbalizing will address the information employed
while performing a given task.
• This model identifies and analyses these verbalizations
and distinguishes them into three kinds:
- Vocalizations of thoughts that are already encoded in the verbal
form (talk aloud).
- Verbalization of a sequence of thought that are held in memory in
some other form, e.g. visually (think aloud).
- Other verbalizations (retrospective reports on thoughts not held in
memory).
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8. Reflection
• The authors in the paper report expert users’ experience with TAP–
“Teaching graduate students in Informatics to think aloud and asking them to reflect on their experience
with using the technique have raised a number of issues. Students complain that they think faster than
they can speak, that their thought processes are much more complex than they can verbalize, and that
thinking aloud interferes with their interaction with the interfaces and the task.”
• It is interesting to note that one particular consequence of Ericsson and Simon’s use of their
model of verbalization is their advice to instruct the subject to “keep talking”. Ericsson and
Simon argue that–
“In their model, verbalization will always lack behind thinking in time, except perhaps in the execution of
very new tasks. This is because thinking in already encoded verbal forms is fast, the activation of “old
thoughts” somewhat slower and only the generation of “new thoughts” is really slow.”
• As two cognitive processes are competing, the process of thinking and the process of
verbalizing, hence the delay.
• The model finally makes the assumption that only introspections, which are verbalizations of
currently heeded thoughts, will enhance investigation into task directed cognitive processes
lead to an information processing paradigm.
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9. Conclusion
• Thinking is much more that what can be explicitly expressed in
words.
• To get access to human cognitive processes, a way forward may be
to develop a practice of introspection; to expand our knowledge
about the reflective activity of the user in the expert-guided think
aloud session.
• The authors argue that access to subjective experience is possible in
terms of introspection where user has to become a participant in
the analysis of his or her own cognitive processes.
• The paper suggests that use of think aloud should have, as a
prerequisite, explicit descriptions of design, test procedure and
framework for analysis.
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